1. Field of the Invention
The present invention relates to an optical imaging device, and more specifically, to a flexible near field optical imaging device including a flexible optical head with thin film layer for formation of dynamic optical nano apertures.
2. Background of the Related Art
As industrialization of nano fusion technologies is progressed, the world market grows at an average annual growth rate of 20% or higher and is expected to reach a 2.5 trillion dollar level in 2020, and major countries establish polices for creating new industry by utilizing nano technologies. Particularly, considering that commercially applied portions of the nano imaging technology are small at present, the economic and industrial value of the nano imaging technology is expected to rise sharply in the future.
Recently, techniques of measuring nano scale structures and physical phenomena are required in a variety of fields, and an optical nano imaging technique is the only technique capable of in-situ, on-machine and in-vivo measurements among the nano scale measurement techniques. Although various measurement systems using a near field optical system such as a Near field Scanning Optical Microscope (NSOM) are developed as an optical measurement method of nano scale which does not make a special effect on a measured object, a measurement system using a generally and widely used single near field optical probe needs a high level technique for controlling a gap by approaching the probe within some tens of nanometers from a sample and has a limit in high-speed/large-area real-time imaging.
Although a parallel near field measurement system having a plurality of near field optical probes is proposed recently, it is almost impossible to make a measurement while maintaining a uniform gap across a wide area by the nature of a near field imaging system in which strict maintenance of a gap to the sample is essentially required. Therefore, development of a nano imaging technique of a new concept appropriate to large-area measurements of an in-situ, on-machine and in-vivo state is required.
Particularly, in the case of the bio/medical field, demands for a disease prediction technique through neurotransmission system analysis, molecule/bacteria imaging and the like are explosively increased as the medical paradigm moves from treatment to prevention, and techniques and products capable of performing real-time diagnosis on in-vivo and mass production thereof are required worldwide.
However, existing nano imaging techniques are disadvantageous in that a living cell cannot be observed since a preprocess such as fixing, dying and the like is required before imaging, and, in addition, when a measurement is conducted using an imaging technique having a resolution of nano unit such as a near field optical microscope or the like, an imaging area is very small as much as μm unit, and a time consumed for imaging is very long, and thus the technique cannot be applied to large-area high-speed imaging, and imaging analysis using an external imaging system should be performed by sampling some cell tissues.
In addition, an existing imaging technique using a near field or a probe should make a measurement while maintaining a gap of some tens of nm. However, if a measured object exercises in real-time or a sample is shaped in a curved surface, not a flat surface, precise real-time imaging cannot be performed since a precise gap to the sample is difficult to maintain and the imaging speed is low in the existing imaging technique.
FIG. 1 is a view showing near field nano imaging, and FIG. 2 is a view showing near field nano imaging, in which a probe is connected in parallel.
As shown in FIG. 1, there is a limit in applying the near field nano imaging to a large area due to the narrow imaging area, and there is a problem in that a gap of some nm level should be maintained for imaging.
FIG. 2 is a view showing a configuration of connecting a probe in parallel to overcome a narrow imaging area of near field nano imaging as shown in FIG. 1. However, as shown in FIG. 2, when the probe is connected in parallel, there is a problem in that if a measurement target is shaped in a curved surface, uniform imaging is difficult to achieve since an area in which near field light is generated and an area in which the near field light is not generated are created. That is, since the shape of a measurement target should have uniformity to apply the near field nano imaging to a large area, application targets are limited.
Furthermore, there is a problem in that it is difficult to control imaging to get an image of a measurement target at a desired position and size in a conventional near field nano imaging method, and it is difficult to acquire various information since only a light source of a single wavelength is used.
In addition, since a nano imaging device is generally capable of performing only surface imaging through a flat surface scanning method, it is difficult to acquire an image in the depth direction of a measured object.